Published online by Cambridge University Press: 06 April 2009
In a recent issue of the Journal of Financial and Quantitative Analysis, Bernhard [2] has pointed out and discussed the seemingly paradoxical possibility that P < 0 even though there is a unique r in the [0, ∞) interval, and that r > it for all t. He showed that this can happen when there are one or more additional values of r in the (−1, 0) interval or when the unique r in the [0, ∞) interval consists of multiple coinciding roots. The further point to be shown here is that it can also happen even when r is unique and simple in the (−1, ∞) interval. Thus the phenomenon is considerably more general than Bernhard had implied.